イアイア★ナイトオブデザイア (romanized in Asian English releases as IAIA★NIGHT OF DESIRE) is a Vocaloid original song by samfree, a prolific producer known throughout the Japanese vocal synth scene. Featuring the voice of IA, a Vocaloid developed by 1st Place with a clear, youthful timbre, the track debuted in maimai GreeN on September 5, 2013, as part of the series' growing library of niconico and Vocaloid content. The song belongs to samfree's "Night Series," a collection of compositions linked by nocturnal imagery and energetic electronic pop production. At 162 BPM, IA's vocals ride over a driving instrumental arrangement, with lyrics that weave together themes of instinct, starlit romance, and desire. The chorus, built around the repeated "イアイア" chant, directly incorporates the voicebank's name as both a lyrical hook and a nod to her identity. In maimai, both the Expert and Master charts were authored by notes designer はっぴー (Happy), whose patterns emphasize the song's rhythmic drive through layered hold sequences and slide formations. The Master chart has been rebalanced multiple times across maimai versions, rising from level 9 at launch to level 11 by the FESTiVAL era, reflecting both the chart's enduring challenge and the game's evolving difficulty standards. The song's in-game genre label also shifted over its lifespan, originally appearing under VARIETY in GreeN before being recategorized as niconico and eventually settling as niconico & VOCALOID from PiNK onward.